U.S. patent application number 15/428219 was filed with the patent office on 2017-08-17 for method of fitting a hearing aid system, a hearing aid fitting system and a computerized device.
This patent application is currently assigned to Widex A/S. The applicant listed for this patent is Widex A/S. Invention is credited to Jesper THEILL.
Application Number | 20170238106 15/428219 |
Document ID | / |
Family ID | 59560588 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170238106 |
Kind Code |
A1 |
THEILL; Jesper |
August 17, 2017 |
METHOD OF FITTING A HEARING AID SYSTEM, A HEARING AID FITTING
SYSTEM AND A COMPUTERIZED DEVICE
Abstract
A method (100) of fitting a hearing aid system comprising
identification of an auditory neuro-synaptopathy of a person based
on the sensitivity of the person to temporal masking, a hearing aid
fitting system, a computerized device (200, 300), a server (302)
hosting a web service and a computer-readable storage medium having
computer-executable instructions, which when executed carry out
said method.
Inventors: |
THEILL; Jesper; (Lynge,
DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Widex A/S |
Lynge |
|
DK |
|
|
Assignee: |
Widex A/S
Lynge
DK
|
Family ID: |
59560588 |
Appl. No.: |
15/428219 |
Filed: |
February 9, 2017 |
Current U.S.
Class: |
381/314 |
Current CPC
Class: |
H04R 25/35 20130101;
H04R 2225/43 20130101; H04R 25/70 20130101; A61B 5/7475 20130101;
A61B 5/123 20130101 |
International
Class: |
H04R 25/00 20060101
H04R025/00; A61B 5/12 20060101 A61B005/12 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 11, 2016 |
DK |
201600088 |
Claims
1. A method of fitting a hearing aid system comprising the steps
of: providing a first test sound having a first intensity level and
a first duration; providing a second test sound, having a second
intensity level and a third duration; providing a period of
silence, in between said first and second test sounds, wherein the
period of silence has a second duration; prompting a person to
detect the second test sound; receiving an input from the person in
response to said prompting; determining the person's sensitivity to
temporal masking based on the input from the person; identifying an
auditory neuro-synaptopathy for the person if the sensitivity to
temporal masking is increased compared to normal hearing persons;
and setting a gain or a hearing aid parameter or selecting a
hearing aid feature based on the result of said identification.
2. The method according to claim 1, wherein the magnitude of the
first intensity level is sufficient to activate the medium
spontaneous-rate nerve-fibres and/or the low spontaneous-rate
nerve-fibres.
3. The method according to claim 1 comprising the further steps of:
determining the duration of the period of silence that makes the
second test sound just noticeable for the person; and determining
that the sensitivity to temporal masking is increased relative to
normal hearing persons if the determined duration of the period of
silence is increased relative to the corresponding duration for
normal hearing persons.
4. The method according to claim 1 comprising the further steps of:
determining the level difference, between the first and the second
intensity levels, that makes the second test sound just noticeable
for the person; and determining that the sensitivity to temporal
masking is increased relative to normal hearing persons if the
determined level difference is decreased relative to the
corresponding level difference for normal hearing persons.
5. The method according to claim 1, wherein the step of determining
the person's sensitivity to temporal masking is carried out for a
plurality of first intensity levels of the first test sound, and
wherein the step of identifying an auditory neuro-synaptopathy for
the person is carried out by determining that the sensitivity to
temporal masking does not decrease for first intensity levels being
sufficiently high to activate the medium spontaneous-rate
nerve-fibres and/or the low spontaneous-rate nerve-fibres.
6. The method according to claim 1, wherein the first and second
test sounds are selected from a group comprising: pure tones,
warble tones and narrow-band noise.
7. The method according to claim 1, wherein the center frequency of
the second test sound is frequency shifted relative to the center
frequency of the first test sound, and wherein the frequency shift
is less than 5% or less than 10% of the center frequency of the
first test sound.
8. The method according to claim 3 wherein the step of determining
the duration of the period of silence, that makes the second test
sound just noticeable for the person comprises the step of: varying
the duration of the period of silence until the second test sound
is just noticeable for the person.
9. The method according to claim 4 wherein the step of determining
the second intensity level, that makes the second test sound just
noticeable for the person comprises the step of: varying the second
intensity level until the second test sound is just noticeable for
the person.
10. The method according to claim 1, wherein the step of selecting
a hearing aid feature based on the result of said identification
comprises selecting the hearing aid feature from a group of
features comprising: frequency contrast enhancement and interleaved
frequency band processing.
11. A non-transitory computer-readable medium storing instructions
thereon, which when executed by a computer perform the following
method: providing a first test sound having a first intensity level
and a first duration; providing a second test sound, having a
second intensity level and a third duration; providing a period of
silence, in between said first and second test sounds, wherein the
period of silence has a second duration; prompting a person to
detect the second test sound; receiving an input from the person in
response to said prompting; determining the person's sensitivity to
temporal masking based on the input from the person; identifying an
auditory neuro-synaptopathy for the person if the sensitivity to
temporal masking is increased compared to normal hearing persons;
and setting a gain or a hearing aid parameter or selecting a
hearing aid feature based on the result of said identification.
12. A hearing test system comprising a computerized device having
an electro-acoustical output transducer, a graphical user
interface, a program storage for storing an executable program, and
a processor for executing said program to perform the following
method: providing a first test sound having a first intensity level
and a first duration; providing a second test sound, having a
second intensity level and a third duration; providing a period of
silence, in between said first and second test sounds, wherein the
period of silence has a second duration; prompting a person to
detect the second test sound; receiving an input from the person in
response to said prompting; determining the person's sensitivity to
temporal masking based on the input from the person; identifying an
auditory neurodegeneration for the person if the sensitivity to
temporal masking is increased compared to normal hearing persons.
Description
[0001] The present invention relates to a method of fitting a
hearing aid system and a hearing aid fitting system. The present
invention also relates to a computerized device configured to
identify an auditory neuro-synaptopathy of a person. The present
invention furthermore relates to a computer-readable storage medium
having computer-executable instructions, which when executed carry
out a method of identifying an auditory neuro-synaptopathy of a
person. The invention further relates to a server hosting a web
service.
BACKGROUND OF THE INVENTION
[0002] Generally a hearing aid system according to the invention is
understood as meaning any system which provides an output signal
that can be perceived as an acoustic signal by a user or
contributes to providing such an output signal, and which has means
which are used to compensate for an individual hearing deficiency
of the user or contribute to compensating for the hearing
deficiency of the user. These systems may comprise hearing aids
which can be worn on the body or on the head, in particular on or
in the ear, and can be fully or partially implanted. However, some
devices whose main aim is not to compensate for a hearing
deficiency may also be regarded as hearing aid systems, for example
consumer electronic devices (televisions, hi-fi systems, mobile
phones, MP3 players etc.), provided they have, however, measures
for compensating for an individual hearing deficiency.
[0003] Within the present context a hearing aid may be understood
as a small, battery-powered, microelectronic device designed to be
worn behind or in the human ear by a hearing-impaired user.
[0004] Prior to use, the hearing aid is adjusted by a hearing aid
fitter according to a prescription. The prescription is
conventionally based on a hearing test that measures the hearing
threshold, resulting in a so-called audiogram, of the performance
of the hearing-impaired user's unaided hearing. The prescription
may be developed to reach a setting where the hearing aid will
alleviate a hearing deficiency by amplifying sound at frequencies
in those parts of the audible frequency range where the user
suffers a hearing deficit in the form of an elevated hearing
threshold.
[0005] A hearing aid comprises one or more microphones, a battery,
a microelectronic circuit comprising a signal processor, and an
acoustic output transducer. The signal processor is preferably a
digital signal processor. The hearing aid is enclosed in a casing
suitable for fitting behind or in a human ear. For this type of
traditional hearing aids the mechanical design has developed into a
number of general categories. As the name suggests, Behind-The-Ear
(BTE) hearing aids are worn behind the ear. To be more precise, an
electronics unit comprising a housing containing the major
electronics parts thereof is worn behind the ear and an earpiece
for emitting sound to the hearing aid user is worn in the ear, e.g.
in the concha or the ear canal. In a traditional BTE hearing aid, a
sound tube is used to convey sound from the output transducer,
which in hearing aid terminology is normally referred to as the
receiver, located in the housing of the electronics unit and to the
ear canal. In some modern types of hearing aids a conducting member
comprising electrical conductors conveys an electric signal from
the housing and to a receiver placed in the earpiece in the ear.
Such hearing aids are commonly referred to as Receiver-In-The-Ear
(RITE) hearing aids. In a specific type of RITE hearing aids the
receiver is placed inside the ear canal. This category is sometimes
referred to as Receiver-In-Canal (RIC) hearing aids. In-The-Ear
(ITE) hearing aids are designed for arrangement in the ear,
normally in the funnel-shaped outer part of the ear canal. In a
specific type of ITE hearing aids the hearing aid is placed
substantially inside the ear canal. This category is sometimes
referred to as Completely-In-Canal (CIC) hearing aids. This type of
hearing aid requires an especially compact design in order to allow
it to be arranged in the ear canal, while accommodating the
components necessary for operation of the hearing aid.
[0006] Some hearing aid systems do not comprise a traditional
loudspeaker as output transducer. Examples of hearing aid systems
that do not comprise a traditional loudspeaker are cochlear
implants, implantable middle ear hearing devices (IMEHD) and
bone-anchored hearing aids (BAHA).Within the present context a
hearing aid system may comprise a single hearing aid (a so called
monaural hearing aid system) or comprise two hearing aids, one for
each ear of the hearing aid user (a so called binaural hearing aid
system). Furthermore the hearing aid system may comprise an
external device, such as a smart phone having software applications
adapted to interact with other devices of the hearing aid system,
or the external device alone may function as a hearing aid system.
Thus within the present context the term "hearing aid system
device" may denote a traditional hearing aid or an external
device.
[0007] It is well known for persons skilled in the art of hearing
aid systems that some hearing aid system users are not satisfied
with results of conventional hearing-aid fitting that primarily is
based on measuring an elevated hearing threshold.
[0008] A subgroup of potential hearing aid users is assumed to
suffer from an auditory neuro-synaptopathy due to aging or ototoxic
drug exposure or noise trauma. This type of hearing deficit may
also be denoted an auditory neurodegeneration if preferring a more
general term. Auditory neuro-synaptopathy is a dysfunction in the
synapses that transmits hearing information from e.g. the inner
hair cells of the cochlea and to nerve-fibres that carry the
hearing information further on to the processing parts of the
brain. A plurality of synapses are required to be activated in
order to provide that a nerve-fibre is activated and transmits the
hearing information.
[0009] Measurement of the hearing threshold cannot generally be
used to diagnose this type of hearing deficiency. Many hearing aid
fitters may therefore be hesitant to suggest or apply potentially
beneficial sound-processing features specifically adapted to
relieve an auditory neuro-synaptopathy, unless a hearing aid
fitting system capable of detecting an auditory neuro-synaptopathy
is available.
[0010] It is therefore a feature of the present invention to
provide a hearing aid fitting system or some other computerized
device capable of detecting an auditory neuro-synaptopathy.
[0011] Such a measurement may also detect hearing deficiencies for
those persons that complain about a problem with understanding
speech in noise, but do not reveal an elevated hearing threshold
(that may also be denoted reduced pure-tone sensitivity). Today,
these persons are not prescribed hearing-aid system treatment and
are therefore left to cope with their hearing deficit.
[0012] According to another aspect it is a feature of the present
invention to suggest a method of fitting a hearing aid system that
comprises detection of an auditory neuro-synaptopathy in a manner
that is time-efficient and easy to execute such that it may be
suitable for implementation as part of a standard hearing aid
fitting procedure.
[0013] It is another feature of the present invention to provide a
hearing aid fitting system capable of suggesting and providing
features specifically directed at relieving an auditory
neuro-synaptopathy.
SUMMARY OF THE INVENTION
[0014] The invention, in a first aspect, provides a method of
fitting a hearing aid system according to claim 1.
[0015] The invention, in a second aspect, provides a
computer-readable storage medium having computer-executable
instructions according to claim 11.
[0016] The invention, in a third aspect, provides a hearing aid
fitting system according to claim 12.
[0017] The invention in a fourth aspect, provides a computerized
device according to claim 13.
[0018] The invention in a fifth aspect, provides a server hosting a
web service according to claim 14.
[0019] Further advantageous features appear from the dependent
claims.
[0020] Still other features of the present invention will become
apparent to those skilled in the art from the following description
wherein the invention will be explained in greater detail.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] By way of example, there is shown and described a preferred
embodiment of this invention. As will be realized, the invention is
capable of other embodiments, and its several details are capable
of modification in various, obvious aspects, all without departing
from the invention. Accordingly, the drawings and descriptions will
be regarded as illustrative in nature and not as restrictive. In
the drawings:
[0022] FIG. 1 illustrates highly schematically a method of fitting
a hearing aid system according to an embodiment of the
invention;
[0023] FIG. 2 illustrates highly schematically a computerized
device according to an embodiment of the invention; and
[0024] FIG. 3 illustrates highly schematically a computerized
device and an external server according to an embodiment of the
invention.
DETAILED DESCRIPTION
[0025] Within the present context the term software application may
be construed to comprise a program storage for storing an
executable program, and a processor for executing said program.
However, the term software application may also be construed to
mean a non-transitory computer readable medium carrying
instructions that may be executed by a computer.
[0026] The inventors have realized that people with auditory
neuro-synaptopathy may be particularly sensitive to temporal
masking. Temporal masking (which may also be denoted
non-simultaneous masking) is the characteristic of the auditory
system where sounds are hidden due to maskers that have just
disappeared. The effect of masking after a strong sound is called
post-masking, and can be in effect up to 200 milliseconds.
[0027] It is presently believed that people with auditory
neuro-synaptopathy may be more sensitive to temporal masking due to
the auditory nerve synapses, which transmits hearing signals from
the inner hair cells and to an auditory nerve-fibre and on to other
parts of the brain for further processing, exhibiting different
characteristics dependent on whether the corresponding auditory
nerve-fibre is adapted to respond to respectively low, medium or
high sound pressure levels. In the following an auditory
nerve-fibre may be construed to comprise both the synapses and the
corresponding nerve-fibre, and in the following an auditory
nerve-fibre may also simply be denoted a nerve-fibre.
[0028] The auditory nerve-fibres that respond to low sound pressure
levels are typically denoted high-spontaneous rate (HSR)
nerve-fibres and are characterized in that their temporal response
is relatively slow. As opposed hereto the auditory nerve-fibres
that respond to the medium and high sound pressure levels typically
exhibit a temporal response that is relatively faster. These
nerve-fibres are typically denoted respectively medium-spontaneous
rate (MSR) nerve-fibres and low-spontaneous rate (LSR)
nerve-fibres. For normal hearing persons the low sound pressure
levels that the HSR nerve-fibres primarily respond to are in the
range between say 0-40 dB SPL, the medium sound pressure levels
that the MSR nerve-fibres primarily respond to are in the range
between say 20-100 dB SPL, and the high sound pressure levels that
the LSR nerve-fibres primarily respond to are in the range between
say 40-120 dB SPL. For persons suffering from a hearing deficit
that results in an elevated hearing threshold the HSR nerve-fibres
will primarily respond to sound pressure levels in the range
between the hearing threshold (i.e. 0 dB SL) and 40 dB above the
hearing threshold (i.e. 40 dB SL), the medium sound pressure levels
that the MSR nerve-fibres primarily respond to are in the range
between say 20-100 dB SL and the high sound pressure levels that
the LSR nerve-fibres primarily respond to are in the range between
say 40-120 dB SL. However, it is noted that for persons suffering
from a more complex hearing deficiency, such as an outer hair cell
loss, the above ranges may be different especially for the sound
pressure levels that the MSR and LSR nerve-fibres primarily respond
to.
[0029] The MSR and LSR nerve-fibres that respond to the medium and
high sound pressure levels are characterized in that they, as
opposed to the HSR nerves-fibres that primarily respond to low
sound pressure levels, comprise two different types of synapses,
wherein the second synapse type that is generally not part of the
HSR nerve-fibres differs from the first type in that the second
synapse type is faster, but also less robust against damage from
e.g. ototoxic drug use or excessive sound exposure. Thus the HSR
nerve-fibres, which primarily comprise nerve-fibres of the first
type, are therefore expected to be slower but also more robust than
the MSR and LSR nerve-fibres.
[0030] Assuming that the synapses of the second type have been
damaged to the extent that they do not function properly anymore,
which may very well be the case because of the vulnerability of
this type of synapses, then this deficit will not impact the
hearing threshold. However, this type of hearing deficit will have
an impact on the sensitivity to temporal masking for the relatively
high sound pressure levels that the MSR nerve-fibres and LSR
nerve-fibres respond to.
[0031] The present invention therefore suggests a test based on the
ability of a person to deal with temporal masking (i.e. the
sensitivity of said person to temporal masking) in order to
diagnose an auditory neurodegeneration such as an auditory
neuro-synaptopathy.
[0032] The hearing aid fitting systems and computerized devices
according to the present invention can therefore be used to
identify persons suffering from auditory neuro-synaptopathy and
hereby provide information of the hearing deficit beyond the
conventional audiogram.
[0033] Additionally the disclosed methods of hearing aid fitting
are advantageous in that the identification and quantification of
an auditory neuro-synaptopathy may be used to prescribe and fit
(which in the following may also be denoted to program) alternative
methods of operating hearing aid systems, e.g. more aggressive
noise-reduction algorithms, whereby persons suffering from this
hearing deficit may achieve greater benefit from wearing a hearing
aid system.
[0034] Reference is first made to FIG. 1, which illustrates highly
schematically a method 100 of fitting a hearing aid system
according to an embodiment of the invention. The method comprises
the steps of: [0035] providing, in a first step 101, a first test
sound having a first intensity level and a first duration; [0036]
providing, in a second step 102, a period of silence, immediately
after said first test sound, wherein the period of silence has a
second duration; [0037] providing, in a third step 103, a second
test sound, immediately after said period of silence, wherein the
second test sound has a second intensity level and a third
duration; [0038] prompting, in a fourth step 104, a person to
identify the second test sound; [0039] receiving, in a fifth step
105, an input from the person in response to said prompting; [0040]
determining, in a sixth step 106, the person's sensitivity to
temporal masking based on the input from the person; [0041]
identifying, in a seventh step 107, an auditory neuro-synaptopathy
for the person if the sensitivity to temporal masking is increased
compared to that of normal hearing persons; and [0042] setting, in
an eighth step 108, a gain or a hearing aid parameter or selecting
a hearing aid feature based on the result of said
identification.
[0043] Pure tones are used as the first and second test sounds.
However, in variations other narrowband test sounds may be used,
such as warble tones or narrow-band noise, wherein narrowband may
be construed to mean that the frequency content of the test sound
primarily is within one hearing aid system frequency band or
alternatively within one of the so called critical bands, that may
also be denoted auditory filters or Bark bands.
[0044] In other variations the second test sound may be slightly
frequency shifted relative to the first test sound in order to
improve the detectability for the test person. Preferably the
frequency shift is less than 10% or even less than 5% of the centre
frequency of the first test sound.
[0045] The intensity level of the first test sound (that in the
following may also simply be denoted first intensity level) is set
to 50 dB SL or selected from a range between 20 dB SL and 80 dB SL.
This range ensures that a sufficient activation of the MSR and LSR
nerve-fibres is provided. Additionally this range of first
intensity levels provides a reasonable compromise between the
limited dynamic range of input intensity levels that may be
available for people suffering from an elevated hearing threshold
and the desire to optimize the precision of the assessment of the
sensitivity to temporal masking by activating as many of MSR and
LSR nerve-fibres as possible. It is a specific advantage to select
the first intensity level based on the dB SL scale, since this
allows the sensitivity to temporal masking between normal hearing
persons and people with an elevated hearing threshold to be
compared in a simple and direct manner.
[0046] The duration of the first test sound is set to be 200
milliseconds or selected from a range between 100 milliseconds and
1 second. This range provides a compromise between the desire to
have a test method that is not too lengthy while on the other hand
ensuring that a sufficient amount of nerve-fibres have been
activated in order to optimize the precision of the assessment of
the sensitivity to temporal masking, because the inventor has found
that the precision may suffer if a higher intensity first test
sound of shorter duration is applied, because the reproducibility,
of the amount of activated nerve-fibres, as a result of the first
test sound, starts to decrease if the duration of the first test
sound becomes too short.
[0047] The intensity level of the second test sound (that in the
following may also simply be denoted second intensity level) is set
to be 20 dB lower than the first intensity level, or the second
intensity level may be selected from a range between 10 dB and 40
dB lower than the first intensity level. It is a specific advantage
to select the second intensity level relative to the first
intensity level because this provides that the determined
sensitivity to temporal masking between normal hearing persons and
people with a conductive, sensorineural or mixed hearing loss with
an elevated hearing threshold is as independent as possible of the
selected intensity level of the first test sound. In a specific
variation the difference, between the first and second intensity
levels, is increased as the first intensity level is increased
because a larger difference generally facilitates the determination
of the sensitivity to temporal masking. However, a too small value
of the second intensity level, say in the range below 10 dB SL may
adversely affect the ability to determine the sensitivity to
temporal masking.
[0048] The duration of the second test sound (that in the following
may also simply be denoted the third duration) is set to be 10
milliseconds or selected from a range between 5 milliseconds and 50
milliseconds. This range provides that the duration of the second
test sound is sufficiently long such that it can be perceived by
the test person while on the other hand generally avoiding that the
duration of the second test sound becomes so long that even people
suffering from increased sensitivity to temporal masking will be
able to perceive the second test sound and hereby making it
impossible to detect a difference in the sensitivity to temporal
masking.
[0049] The duration of the period of silence (that in the following
may also simply be denoted the second duration) between the two
test sounds is varied iteratively until the second duration that
makes the second test sound just noticeable has been determined.
According to the present embodiment the duration of the period of
silence is initially set to 20 milliseconds and may subsequently be
varied in the range between say 5 milliseconds and 200
milliseconds. The upper limit of this range is selected to
correspond to the generally accepted upper limited for the duration
of temporal masking and the lower limit is selected in order to
provide a sufficiently long period of silence such that the test
person may distinguish the second test sound from the first test
sound.
[0050] According to the present embodiment the duration of the
period of silence (i.e. the second duration) is iteratively varied,
depending on the responses of the test person, until the duration
of the period of silence that makes the second test sound just
noticeable has been determined, and in case the determined just
noticeable second duration is significantly longer than a
corresponding value for normal hearing persons, then an auditory
neurodegeneration is identified.
[0051] In a variation the second duration that makes the second
test sound just noticeable is determined for a plurality of first
intensity levels, and in case the second duration that makes the
second test sound just noticeable does not decrease for some high
value of the first intensity levels relative to some lower value of
the first intensity level, then an auditory neurodegeneration is
identified, because this case reflects that the fast MSR
nerve-fibres or the fast LSR nerve-fibres or both of them have been
damaged in some way and consequently don't provide the expected
reduction in sensitivity to temporal masking. The high value of the
first test sound intensity level is construed to mean that the
first test sound intensity level is sufficiently high to activate
the MSR and/or LSR nerve-fibres, which is the case for first
intensity levels above 50 dB SL, wherefrom it follows that the
lower value of the first intensity level is selected from the range
between 10-50 dB SL.
[0052] According to a more specific variation the first intensity
level is initially set to 40 dB SL and then increased in steps of
10 dB until approaching the uncomfortable level of the test
person.
[0053] According to a second embodiment an auditory
neuro-synaptopathy is identified based on a determination of the
level difference between the first and the second intensity levels
that makes the second test sound just noticeable. According to one
specific variation the first intensity level as well as the first,
second and third durations are given values corresponding to the
first embodiment, and the second intensity level is varied
iteratively until the lowest intensity level that makes the second
test sound just noticeable has been determined. Thus according to
this specific variation the duration of the period of silence is
set to 20 milliseconds, which will make temporal masking important
with respect to the ability of a person to detect the second test
sound because the refractory period of the nerve-fibres (or more
precisely the slow synapses of the nerve-fibres) is typically in
the range of 200 milliseconds. In further variations the duration
of the period of silence is selected from a range between 10 and 50
milliseconds.
[0054] According to the second embodiment an auditory
neuro-synaptopathy is identified in case the determined level
difference, between the first and the second intensity level, that
makes the second test sound just noticeable is significantly higher
than the corresponding value for normal hearing persons.
[0055] In a more specific variation the level difference, between
the first and the second intensity level, that makes the second
test sound just noticeable is determined for a plurality of first
intensity levels, and in case the determined level difference does
not increase for some high value of the first intensity level,
relative to a determined level difference for some lower value of
the first intensity level, then an auditory neurodegeneration is
identified, because this case reflects that the fast MSR
nerve-fibres or the fast LSR nerve-fibres or both of them have been
damaged in some way and consequently don't enable the person to
take advantage of the reduced sensitivity to temporal masking that
the fast nerve-fibres provide if functioning correctly. The high
value of the first test sound intensity level is construed to mean
that the first test sound intensity level is sufficiently high to
activate the MSR and/or LSR nerve-fibres, which is the case for
first intensity levels above 40 dB SL, wherefrom it follows that
the lower value of the first intensity level is selected from the
range between 10-40 dB SL.
[0056] According to further variations of the disclosed embodiments
the method is carried out with a plurality of test tones with
different frequency content in order to characterize the frequency
dependence of a possible auditory neuro-synaptopathy. According to
a more specific embodiment the method is carried out with a
plurality of test tones that each represent a hearing aid frequency
band.
[0057] Reference is now made to FIG. 2, which illustrates highly
schematically a computerized device 200 according to an embodiment
of the invention. The computerized device 200 comprises a software
application 201, a graphical user interface 202, a digital signal
processor (DSP) 203 and an electro-acoustical output transducer
204.
[0058] FIG. 2 illustrates how a person 205 through the graphical
user interface 202 may communicate interactively with the
computerized device 200 in a manner controlled by the software
application 201. The software application 201 is furthermore
adapted to interact with the DSP 203 such that the
electro-acoustical transducer 204 can be used to provide a desired
acoustical test signal.
[0059] In correspondence with the first embodiment according to
FIG. 1 the computerized device 200 is adapted to provide a first
test sound at a first intensity level and a second test sound at a
second intensity level, using the electro-acoustical output
transducer 204, wherein the first test and second test sounds are
separated by a period of silence of a certain duration.
[0060] Furthermore the computerized device 200 is adapted to prompt
a person to respond each time the second test sound is detected,
which may not be the case if the duration of the period of silence
between the first and second test sounds is so short that the
second test sound is masked by the first test sound, or the second
test sound may not be detected if the second intensity level is not
large enough relative to the first intensity level due to partial
masking by the first test sound. The computerized device 200 is
also adapted to receive, through the graphical user interface 202,
an input from the person in response to said prompting, wherein
said input represents the person's sensitivity to temporal masking
because a positive detection of the second test sound means that
the second test sound has not been temporally masked by the first
test sound.
[0061] The shorter the period of silence can be while still
allowing the second test sound to be detected, the lower the
persons sensitivity to temporal masking. Further, the higher the
level difference between the first and the second test sounds can
be while still allowing the second test sound to be detected, the
lower the persons sensitivity to temporal masking.
[0062] Therefore the computerized device 200 is adapted to vary up
and down the duration of the period of silence between the first
and second test sound, based on the response from the person, until
the second test sound is perceived as just noticeable by the
person. Additionally or alternatively the computerized device 200
may be adapted to vary up and down the second intensity level,
based on the response from the person, until the second test sound
is perceived as just noticeable by the person.
[0063] Finally the computerized device 200 is adapted to identify
an auditory neuro-synaptopathy for the person if the sensitivity to
temporal masking is not reduced relative to normal hearing persons.
Additionally or alternatively the computerized device 200 may be
adapted to identify an auditory neuro-synaptopathy for the person
if the sensitivity to temporal masking for some high value of the
first test sound intensity level is not reduced relative to the
sensitivity to temporal masking at some relatively lower value of
the first test sound intensity, wherein the high value of the first
test sound intensity level is sufficiently high to activate the MSR
and/or LSR nerve-fibres. Wherein the high value of the first test
sound intensity level therefore is construed to mean that the first
test sound intensity level is sufficiently high to activate the MSR
and/or LSR nerve-fibres, which is the case for first intensity
levels above 40 dB SL, wherefrom it follows that the lower value of
the first intensity level is selected from the range between 5-40
dB SL.
[0064] In a specific variation the identification of an auditory
neuro-synaptopathy may be used as input to a hearing aid fitting
system, whereby alternative processing features directed
specifically at relieving an auditory neuro-synaptopathy may be
selected.
[0065] In a variation the computerized device 200 is adapted to
identify an auditory neuro-synaptopathy if the duration of the
period of silence between the first and second test sounds that
makes the second test sound just noticeable is longer than a first
threshold that is in the range between say 5 and 50
milliseconds.
[0066] In another variation the computerized device 200 is adapted
to identify an auditory neuro-synaptopathy if the level difference,
between the first intensity level and the second intensity level,
that makes the second test sound just noticeable, is larger than a
first threshold that is in the range between say 5 dB and 20
dB.
[0067] However, as will be clear from the preceding disclosure, the
other parameters determining the applied test sounds also need to
be considered in order to find an optimum setting for the test.
[0068] In a further variation the magnitude of the duration of the
period of silence between the first and second test sounds that
makes the second test sound just noticeable may be used as input to
a hearing aid fitting system, whereby parameters of alternative
processing features directed specifically at relieving an auditory
neuro-synaptopathy may be set dependent on the severity of the
auditory degeneration.
[0069] In further variations the computerized device 200 is adapted
to be part of a conventional hearing aid fitting system, wherein
the person to be tested is exposed to the test sounds from
loudspeakers controlled by the computerized device and wherein the
person responds by signaling his response to a hearing care
professional (who may also be denoted a hearing aid fitter) who
subsequently inputs the responses to the computerized device. In a
more specific variation the computerized device controls at least
one hearing aid worn by the person, whereby the test sounds can be
provided by the hearing aids.
[0070] Reference is now made to FIG. 3, which illustrates highly
schematically a computerized device 300 and an external server 302
according to an embodiment of the invention. The computerized
device 300 comprises basically the same elements as the
computerized device 200 from the embodiment of FIG. 2, except in so
far that the functionality, which in the embodiment of FIG. 2 is
provided by the software application 201, in the embodiment of FIG.
3 is provided by a web service that is hosted on the external
server 302 and may be accessed using the web browser 301.
[0071] In variations of the FIGS. 2 and 3 embodiments the
computerized device may be a smart phone, a tablet computer, a
portable personal computer or a stationary personal computer.
According to the embodiments of FIG. 2 and FIG. 3 the
electro-acoustical transducer 204 is a traditional loudspeaker.
However, the loudspeaker provides the acoustical test signal to
both ears simultaneously, which may be less advantageous in some
cases, e.g. if the person only has a hearing deficit in one ear. In
variations the software application is therefore set up to provide
an acoustical test signal that is selectively provided to either
the left ear or the right ear using a set of standard headphones,
earphones or even hearing aids connected to the computerized
device.
[0072] It is a specific advantage of the present invention that it
provides a quantitative measure of the auditory neuro-synaptopathy,
such that the quantitative measure may be used to select the most
appropriate processing for the person. As one example a person
requiring a very long period of silence between a first and a
second test sound in order to avoid temporal masking of the
subsequent second test sound, which indicates a serious auditory
neuro-synaptopathy, may benefit from more aggressive noise
reduction algorithms or alternative processing schemes (which may
also be denoted hearing aid features) directed at relieving the
amount of sound that the auditory nerves are exposed to. Examples
of such alternative hearing aid features comprise frequency
contrast enhancement and interleaved frequency band processing.
[0073] The method of frequency contrast enhancement in a hearing
aid system may be described by the steps of: [0074] providing an
electrical input signal representing an acoustical signal from an
input transducer of the hearing aid system; [0075] splitting the
input signal into a first plurality of frequency bands; [0076]
determining a measure of the signal variability for each band of a
second plurality of frequency bands; [0077] determining a threshold
level based on the determined measures of the signal variability
for each band of the second plurality of frequency bands; [0078]
applying a first gain to a frequency band based on an evaluation of
the determined measure of the signal variability for said frequency
band relative to the threshold level; [0079] combining the first
plurality of frequency bands into an electrical output signal; and
[0080] using the electrical output signal for driving an output
transducer of the hearing aid system.
[0081] The method of interleaved frequency band processing in a
hearing aid system may be described by the steps of: [0082]
providing an electrical input signal representing an acoustical
signal from an input transducer of the hearing aid system; [0083]
splitting the input signal into a plurality of frequency bands;
[0084] forming a first group of frequency bands and a second group
of frequency bands, wherein the first group of frequency bands
comprises frequency bands that are interleaved with respect to
frequency bands comprised in the second group of frequency bands;
[0085] alternating between selecting the first group of frequency
bands or the second group of frequency bands; [0086] processing the
selected frequency bands in a first manner, hereby providing
processed selected frequency bands; [0087] processing the
non-selected frequency bands in a second manner such that the
non-selected frequency bands are attenuated relative to the
selected frequency bands, hereby providing processed non-selected
frequency bands; [0088] providing an output signal based on the
processed selected and non-selected frequency bands; and [0089]
using the output signal to drive an output transducer of the
hearing aid system.
[0090] In a specific variation of the disclosed embodiments and
their variations the final method step of setting a gain or a
hearing aid parameter or selecting a hearing aid feature may be
omitted. Hereby a method of diagnosing an auditory
neuro-synaptopathy results.
[0091] Generally the embodiments according to FIGS. 1-3 and their
variations may be implemented based on a computer-readable storage
medium having computer-executable instructions, which when executed
carry out the methods disclosed with reference to FIGS. 1-3.
[0092] Generally any of the disclosed embodiments of the invention
may be varied by including one or more of the variations disclosed
above with reference to another of the disclosed embodiments of the
invention. Thus the disclosed method embodiment may also be varied
by including one or more of the hearing aid system variations.
[0093] According to still other variations, the present invention
may be implemented for any audio device comprising an
acoustical-electrical input transducer and an output transducer
adapted to provide a perception of audio in a human being. Head
sets, personal sound amplifiers and smart phones are examples of
such audio devices.
* * * * *